Saturday, January 12, 2013

Over at the Bolger group there is yet another discussion on plywood...

Now, I'm all for using good plywood and materials in boats I own or build but there is a point where it gets both counterproductive and just a little bit nuts.

For one, being the cynical bastard that I happen to be, I'm just not impressed with various grades or numbers stamped into a sheet of ply. I've picked through far too many sheets of high priced stamped and approved plywood that had serious voids or delams to lose my faith in the magic of numbers like "1088" or the incantation "Lloyd's" even when made by the expensive folks.

Sadly, since most plywood is manufactured these days in countries that play real fast and loose with things like patents, trademarks, and copyright, it's a sure bet that a lot of that Lloyd's 1088 BS ply at the local marine store ain't.

So, what I do is actually look at the wood in question instead of looking for stamps. Sure, it's a pain but in the end I know what I'm working with. More importantly, before I do a big project I actually work with the stuff and test it...

I think that's called taking some responsibility.

Last year I built our stretched Tortoise/Brick using the truly awful locally available pressure treated exterior grade ply because it was the only 1/4" ply available on the island and I needed a boat ASAP so could not wait to find something better.

Guess what? You guessed it, the plywood turned out really good. Part of my initial distaste for the wood is the pressure treating gives it a sickly green tint and causes some micro checking. A few test pieces I've left untreated on deck as tests have weathered really well with no delamination or interior ply issues which is saying a lot in the Caribbean. The greenish tint is nonproblematic because it gets glassed and painted and as for the micro checking a light sanding makes it all nice. So yeah, I'd build a boat with it.

Which, I should add, is not to say I'd advise you to build a big boat project with the cheap-ass treated exterior plywood available at your local lumber yard because it could be truly heinous stuff more akin to cardboard than to wood. You'd have to make that decision for yourself after seriously looking at it, as well as doing some testing to make sure it is up to the task...